Antiseptic preparation of patients for surgery conventionally includes a 3-10 minute scrubbing of the affected area with a soap solution followed by the application of a water soluble antiseptic paint solution. These solutions are generally applied with saturated sponges that are attached to a blade or held with forceps. The sponges are saturated by soaking in open pans of solution. Numerous devices have been developed in an attempt to prevent the dripping of solution associated with the original technique. Another goal was to reduce the time required for application of the antiseptic solution.
An important problem associated with the original prior art devices developed to apply surgical prep solutions was the lack of control of the delivery of the liquid to the sponge in a manner that prevented dripping. Additional problems encountered with such devices include reliability of rupturable surfaces, manufacturing complexity and inappropriate geometries.
U.S. Pat. Nos. 4,415,288; 4,507,111; and 4,498,796 describe surgical scrub devices that include a liquid containing, rupturable, cylindrical cartridge which is slidable within a tubular handle having one or two longitudinally oriented hollow spikes that communicate to recesses in the interior of a sponge. Sliding the cartridge in the tubular handle causes the spikes to rupture one end of the cartridge. Liquid from the cartridge flows through the lumen of the spikes to the sponge. Liquid can flow through the spikes by gravity or by application of external pressure by deforming a flexible handle and cartridge. In order for liquid to flow by gravity from this device, air must be entrained into the cartridge through the sponge and at least one hollow spike. For the following two reasons, this is not a reliable and predictable means to control the rate of delivery of liquid to the sponge. First, as the sponge becomes wet its air permeability decreases thereby restricting the entrainment of air. Second, hollow tubes with sufficiently small inside diameters to effectively meter the liquid flow rate to prevent dripping tend to "air lock" due to the surface tension of the liquid. Although external pressure can be applied to a flexible device, in practice it is very difficult to deliver precisely the correct volume of liquid to saturate the sponge without dripping.
U.S. Pat. No. 4,342,522 describes a roll on dispenser which includes a porous open cell foam membrane deformable by an applicator ball to regulate the dispensation of controlled amounts of powders. The amount of material dispensed is dependent upon the porosity of the membrane which is dependent upon the degree of deformation of the membrane by the ball upon operation of the dispenser.
U.S. Pat. No. 3,393,963 discloses a dispenser for liquids which has particular utility in applying deodorants, perfumes, liquid lipsticks and the like. The device includes a container holding a supply of liquid, a reservoir body mounted on the outlet of the container and an applicator membrane mounted over, but spaced apart, from the reservoir member. Both the reservoir body and the membrane are made from elastic, porous, preferably foamed material. In use, the dispenser is shaken so as to cause liquid to flow into the porous reservoir member. The porous membrane is then pressed against the skin of the body, causing it to contact the upper surface of the porous reservoir body so that liquid contained therein is pressed through the porous membrane for application to the skin. The amount of liquid to be applied to the skin is regulated by pressure exerted during application of the liquid.
U.S. Pat. No. 4,183,684 describes a fluid dispenser that includes a liquid-containing ampoule in a flexible housing. A porous pad element which may include a gauze like layer and a sponge layer is disposed over the bottom opening. The liquid is released to the porous pad by crushing the ampoule through the flexible housing walls.
Coassigned U.S. Pat. No. 4,925,327, which is hereby incorporated by reference, describes a liquid applicator which incorporates a rigid, porous metering insert to regulate the flow rate of liquid into a sponge. The metering insert is disposed between the applicator handle and a foam sponge covering the major orifice of the handle. The applicator handle incorporates a vent to entrain air into the applicator as liquid flows through the metering element into the sponge. A bonding insert comprised of a thermoplastic or heat activatable material filled with an inductively active material is adapted to bond the applicator handle, metering insert and sponge together. This applicator, while an improvement over the art due to its dripless nature, employs a relatively expensive porous metering insert which is difficult to manufacture so as to provide reproduceable units.